Potted plants of all kinds, whether in the house, greenhouse or outside, need repotting eventually. There are several reasons, the most obvious being that they simply get larger and top-heavy. Most houseplants don't need repotting that often because, if we give them plenty of liquid fertilizer in the growing season, they won't be short of nutrients and should therefore be healthy.Another reason why we pot on our plants is that many are sold in peat-based and peat-type compost. As this ages, it decomposes, and the roots suffer because of lack of air. We may also want to do some potting so we can divide our plants and make more. This gardening tutorial teaches you when and how you should repot your plants.